Citroen risked and Citroen was rewarded. The Versailles-based team had committed itself to 'Project M43' and the building of a test-hack World Touring Car Championship machine before the introduction of TC1 regulations for 2014 was rubber-stamped.

The move, along with throwing resources at an intensive year of testing, transformed a World Rally Championship-winning team into a circuit racing virtuoso. The foundations for a record-breaking season had been laid.

The three Citroen C-Elysee racers, Yvan Muller, Sebastien Loeb and Jose Maria Lopez, arrived at the Marrakesh season-opener in April carrying a performance advantage of daunting magnitude.

About Peter Mills

He was Autosport's World Series by Renault correspondent from 2006 to 2011, during which time he charted 12 future grand prix drivers' progression through the ranks, and he returned to this championship in 2015 after stints covering the World Touring Car Championship and Auto GP. Alongside his core role, Peter covered a variety of international Formula 3 events plus FIA GT and Superleague Formula rounds. He continues as Autosport's Formula V8 3.5 correspondent alongside a new role at LAT Photographic.

How the post-Renault 3.5 series is shaping upWhen Renault ended its support of its 3.5 Formula, there were fears about the category's future. But as PETER MILLS explains, the rebadged FV8 3.5 series has retained an appeal to drivers1454457600

The all-time FR3.5 top 10An era ended in 2015 as Renault withdrew its backing of Formula Renault 3.5. GLENN FREEMAN and PETER MILLS pick the 10 best drivers from the World Series by Renault years1452211200

How Britain's next F1 prospect grew upOliver Rowland's path to Formula Renault 2015 champion and Formula 1 hopeful has not been smooth. PETER MILLS tracks his progress and growth with those who have seen it first hand1448236800F1

The top 10 FR3.5 drivers of 2015The 2015 Formula Renault 3.5 season will be notable for being the last with the French company's backing but also produced a worthy champion in Oliver Rowland. PETER MILLS evaluates this year's crop of drivers1447718400

How Sauber created its greatest legacyIn the latest part of the series celebrating 50 years of the much-loved Swiss outfit, we examine how Sauber's partnership with Mercedes and its famous junior drivers helped produce its greatest legacy in racing1591315200WEC

What makes a great racing circuit?OPINION: F1 circuit design has changed over the years, and the old public-road layouts have given way to purpose-built autodromes. But what makes a great circuit, and could 'classic'-influenced designs offer a way for F1 to return to its roots?1591228800F1

The twin-keel car that took Sauber to new heightsSauber's opening years in Formula 1 were often spent struggling against the tide, but an innovative suspension design for 2001 and a pair of raw, young talents behind the wheel helped the Swiss squad to the front of the midfield order1591228800F1

Please note that unauthorised reproduction or translation of any content (including words, data, information, photos, videos and any other intellectual property) published on this page and any other copyrighted content published on Autosport.com is strictly prohibited. Please see our terms and conditions for further information.